1. Field of the Invention
The present invention relates to a flexure bland for constructing a suspension for a circuit wire integrated type magnetic head and a method of manufacturing the same, and particularly to a flexure blank structured such as to be electrically connected with a relay flexible circuit board for connecting to an external circuit in a reliable manner, and a method of manufacturing the same.
2. Description of the Related Art
This kind of suspension for the circuit wire integral type magnetic head is constituted by a load beam and a flexure blank, and the flexure blank is connected to an external circuit via the relay flexible circuit board.
FIG. 2 is a cross sectional view which shows a schematic arrangement of the connecting portion of the flexure blank mentioned above and the relay flexible circuit board. A terminal portion or the connecting portion of the conventional flexure blank is structured such that an opening portion 22 for connection is provided at a predetermined position of an insulating base layer 20 made of a polyimide resin or the like, a conductive layer 23 made of a copper or the like and including a predetermined circuit wire pattern is formed on an upper surface of the insulating base layer 20 in such a manner as to surround the opening portion 22, and as shown in FIG. 2, an anticorrosive conductive layer 25 made of a gold or the like is formed on an upper surface of the conductive layer 23 in this connecting portion via a barrier conductive layer 24 made of a nickel or the like.
The conductive layer 23, the barrier conductive layer 24 and the anticorrosive conductive layer 25 mentioned above can be formed in accordance with an additive method such as an electrolytic plating or the like, and this kind of flexure blank is coated with a surface protecting layer 26 made of a polyimide resin or the like including the circuit wire pattern in such a manner as to properly expose the connecting portion mentioned above.
However, in accordance with the structure of the connecting portion of the flexure bland mentioned above, there is a case that an end portion 21 of the insulating base layer 20 positioned at the opening portion 22 for connection protrudes and is formed so as to fringe the conductive layer 23, the barrier conductive layer 24 and the anticorrosive conductive layer 25 in the opening portion 22.
As mentioned above, when the end portion 21 of the insulating base layer 20 protrudes to the opening portion 22 for connection, there is generated a case that a solder is neither sufficiently applied nor expended to a whole of the connecting portion constituted by the conductive layer 23, the barrier conductive layer 24 and the anticorrosive conductive layer 25 and an electric connection can not reliably performed since a wetting property of a solder 29 is bad in the protruding end portion 21 of the insulating base layer 20 in the case of bringing the relay flexible circuit board for connecting to the external circuit in which a predetermined circuit wire pattern 28 is formed on an upper surface of the insulating base member 27 into contact with the opening portion 22 in the connecting portion of the flexure blank mentioned above by using the solder 29 in the manner shown by an arrow.
Accordingly, the present invention provides a flexure blank having a connecting portion which can be electrically connected to a relay flexible circuit board for connecting to an external circuit in a reliable manner, and a method of manufacturing the same.
In accordance with the present invention, there is provided a flexure blank of a suspension for a circuit wire integral type magnetic head which is electrically connected to a relay flexible circuit board for connecting to an external circuit, wherein an opening portion is provided in a connecting portion of the flexure blank, and an opening end portion of an insulating base layer is coated with a conductive member without exposing the opening end portion of the insulating base layer in the connecting portion.
In this case, a lower surface of the conductive member of the opening portion in the connecting portion of the flexure blank can be structured such as to form the same surface as the lower surface of the insulating base layer, and the lower surface of the conductive member of the opening portion in the connecting portion can be constructed by a grounding conductive layer made of a chrome.
Then, the flexure blank of this kind can be manufactured in accordance with steps of forming an insulating base layer in a pattern which can form an opening portion necessary for a connection with a relay flexible circuit board used for connecting to an external circuit, on an upper surface of a spring metal layer, at least forming a grounding conductive layer which has an improved solder wetting property and is not corroded by an etching fluid in an etching step with respect to an unnecessary portion of the spring metal layer, on a surface of the insulating base layer and a surface area of an exposed spring metal layer by sputtering means, next, forming a plating resist pattern at a position of forming the opening portion on the surface of the grounding conductive layer, successively forming a desired conductive layer and anticorrosive conductive layer in the connecting portion by electrolytic plating means at a stage of forming the other plating resist patterns in accordance with a pattern which can form the connecting portion, thereafter, peeling and removing the plating resist pattern, further, etching and removing an unnecessary area of the grounding conductive layer so as to form the connecting portion, thereafter, peeling and removing the etching resist pattern which becomes unnecessary at the etching process so as to form the opening portion in the connecting portion, next, etching and removing an unnecessary area of the spring metal layer including the connecting portion, and finally etching and removing an area of the grounding conductive layer which is exposed to the opening portion so as to form a penetrating opening portion in the connecting portion.
In this case, at a stage of etching and removing the unnecessary area of the grounding conductive layer so as to form the connecting portion, it is possible to form a surface protecting layer in such a manner as to properly expose the connecting portion including the other circuit wire pattern, and the grounding conductive layer can be formed by a sputtering using a chrome.